Subject: Re: ok but why or what are we looking for
Date: Jan 04, 2006 @ 02:19
Author: aletheiak ("aletheiak" <aletheiak@...>)
Prev Post in Topic Next [All Posts]
Prev Post in Time Next
--- In BoundaryPoint@yahoogroups.com, "Hugh Wallis" <hugh@o...> wrote:
>
> Each entry made records the actual WGS84 coordinates displayed on a GPSr
> device that is positioned at a physical marker which is marking the Prime
> Meridian. The point is to demonstrate, pursuant to the preceding
> conversation here, that the choice of datum when reporting Lat and Long is
> relevant. Frequently the WGS84 reading will show other than 0° 0.000" E/W
> because different datums (data ?) than WGS84 have been used when placing the
> physical markers. This is not a scientific survey of course, nor can it be
> used in any way to deduce errors elsewhere. It is simply for illustration
> and one of the larger collections of such "in the field" reports of such
> deviations that I am aware of. It adds additional information to what Roger
> found from Google Earth.
>
>
> _____
>
> From: BoundaryPoint@yahoogroups.com [mailto:BoundaryPoint@yahoogroups.com]
> On Behalf Of aletheiak
> Sent: Tuesday, January 03, 2006 4:46 PM
> To: BoundaryPoint@yahoogroups.com
> Subject: [BoundaryPoint] ok but why or what are we looking for
>
>
> --- In BoundaryPoint@yahoogroups.com, "Hugh Wallis" <hugh@o...> wrote:
> >
> > Take a look here where the difference between WGS84 and various other
> > "observations" is documented at various locations along the prime meridian
> >
> > http://tinyurl.com/76jv4
> >
> >
> > _____
> >
> > From: BoundaryPoint@yahoogroups.com [mailto:BoundaryPoint@yahoogroups.com]
> > On Behalf Of Roger McCutcheon
> > Sent: Tuesday, January 03, 2006 6:20 AM
> > To: BoundaryPoint@yahoogroups.com
> > Subject: Re: [BoundaryPoint] Four pointer
> >
> >
> > I went to maximum magnification on Google Earth and found that it did
> indeed
> > show zero longitude as being about three quarters of the way to the far
> side
> > of Black Heath Avenue, to the east of the Zero Meridian in the Royal
> > Observatory, so then I went to the Prime Meridian site and found that "the
> > zero meridian on the WSG84 datum, which is about 100 metres to the east of
> > the line marked at Greenwich, is an average of the various continental
> > movements", so we need not worry: someone is paying attention! Roger
> > McCutcheon.